Fix +- buttons wrap behavior in quiz creation for small resolutions

[MisRob]

Summary

• do not break questions number buttons (+-) in quiz creation
• add grid to ensure that +- buttons are always on the same line as input
• remove obsolete styles from CreateExamPage/index.vue

Small

Before	After

Medium

Large

Reviewer guidance

Check "Number of questions" input together with +- buttons for various resolutions on quiz creation page.

References

#6893

---

Contributor Checklist

PR process:

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Testing:

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

Reviewer Checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[codecov]

Codecov Report

Merging #6981 into app-support will not change coverage.
The diff coverage is n/a.

Impacted Files	Coverage Δ
...ach/assets/src/views/plan/CreateExamPage/index.vue	0.00% <ø> (ø)

[jonboiser]

Looks good!